Cihat Boyraz

Synthesis & characterization of tetrahedrite compounds for thermoelectric applications

Thermoelectric materials have attracted much attention due to their potential applications in conversion of heat into electrical power or vice versa to cool the heat-generating elements using electrical power. Tetrahedrite is copper antimony sulfosalt mineral with the formula of Cu₁₂Sb₄S₁₃, where Cu could be partially replaced by another 3d (Mn, Ag, Al, Cr, Zn, Fe) or other (4d,5d) metal. This group of compounds is very prospective for large-scale thermoelectric applications. The compounds could be represented by common formula of the compound Cu_10-xM_2-xSb_4-yQ_yS_13-zTz. M=Au, Mn, Ag, Al, Cr, Zn, Fe; Q=As, Sn, Zn, Pb; Z=O, Se. The procedure of solid state reaction for tetrahedrite powder samples of various composition have been developed. The single phase tetrahedrite samples of Cu₁₂Sb₂As₂S₁₃, Cu_11.8Au_0.2Sb₄S₁₃, and Cu₁₀Fe₂Sb₄S₁₃ have been synthesized as proved by XRD. Characterization of their magnetic properties by VSM PPMS have been done.

Morphology And Luminescence Characteristics of Yttriumdisilicate Doped with Yb3+, Er3+(Ho3+) and Tm3+

1 Marmara University, Department of Mechanical Engineering, Goztepe Campus, 34722, Istanbul, Turkey cboyraz@marmara.edu.tr 2 Marmara University, Department of Physics, Goztepe Campus, 34722, Istanbul, Turkey merdem@marmara.edu.tr 4 Marmara University, Department of Chemistry, Goztepe Campus, 34722, Istanbul, Turkey mekmekci@marmara.edu.tr 4 Marmara University, Department of Physics, Goztepe Campus, 34722, Istanbul, Turkey ctav@marmara.edu.tr 5 Marmara University, Department of Physics Engineering, Maslak Campus, 34469, Istanbul, Turkey gozenl@itu.edu.tr